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Laser treatment of leg veins: Physical mechanisms and theoretical considerations.

BACKGROUND AND OBJECTIVES: A discussion of laser treatment of leg veins is based on a review of the literature, theoretical analysis, and the clinical experiences of the authors. Theoretical computations are discussed within the context of clinical observations. STUDY DESIGN/MATERIALS AND METHODS: A Monte Carlo model is used to examine volumetric heat production, fluence rate, and temperature profiles in blood vessels at 1,064 and 532 nm wavelengths with various beam diameters, vessel diameters, and pulse durations. RESULTS: Clinical observations, Monte Carlo results, and a review of the literature suggest that longer wavelengths and longer pulses durations favor vessel contraction over intraluminal thrombosis. Monte Carlo simulations show that longer wavelengths are more likely to uniformly heat the vessel compared to highly absorbing wavelengths. Methemoglobin production causes deeply penetrating wavelengths to generate more volumetric heat for the same input radiant exposure. CONCLUSIONS: Clinical observations and models support the role of long wavelengths and long pulses in optimal clearance of most leg telangiectasias.

Humans↗

Facial teleangectasias: our experience in treatment with IPL.

BACKGROUND AND OBJECTIVES: Facial teleangectasias can be a relevant cosmetic problem, which the patient usually hides with a thick layer of makeup. This study will describe the response on these vascular lesions using the intense pulsed light (IPL) source. METHODS: Five hundred eighteen consecutive patients were treated with Photoderm VL (Lumenis Ltd.). The average age of patients of various skin types (Fitzpatrick I to IV) was 48.5 years. They were subjected to a mean of 1.69 treatments (range 1-9) followed up 48 hours, 72 hours, 1 week, 3 weeks, and 1 month after each treatment. All patients were followed up after 2 months from the last treatment and the percentage of clearance was assessed by comparing pre- and post-treatment photographs. The patients also answered a questionnaire in which they expressed personal satisfaction. The physicians evaluation was also recorded on the same form. RESULTS: Patients (87.64%) presented a clearance of 75%-100%. The results appear not correlated with lesions size, age, skin type but with operator experience. Minimal side adverse effects occurred in 20% of the patients. CONCLUSION: The IPL source, Photoderm VL, can be considered an alternative or a supplement to the existing laser devices for facial teleangectasias treatment.

Adolescent↗

Comparative treatment of small diameter (< or =400 microm) vascular lesions using extended pulse dye lasers.

BACKGROUND AND OBJECTIVES: Extended-pulse dye lasers (EPDL) are commonly used to treat a variety of vascular lesions. This study evaluated whether differences in pulse formats and cooling methods might affect outcome in the treatment of small facial telangictasia. STUDY DESIGN/MATERIALS AND METHODS: Ten subjects presenting with symmetric, bilateral facial telangiectasia were studied. Each side of the face was treated with either the V-Startrade mark smart-cool air cooling (Cynosure, Inc.) (VS) or V-beam DCD cooling (Candela, Inc.) (VB) EPDL treatments with both systems were undertaken with a 10-milliseconds pulse duration, 1 J/cm(2) below the purpuric threshold, with up to three passes. RESULTS: Treatment clearance with the VS EPDL occurred with a lower fluence, using fewer passes than with the VB EPDL (P < 0.05). CONCLUSIONS: Although both the currently popular EPDL systems are highly effective in the treatment of small facial telangiectasia, clinical differences can be seen between these two systems.

Cryotherapy↗

Optimal pulse durations for the treatment of leg telangiectasias with a neodymium YAG laser.

BACKGROUND: Leg veins can be effectively treated with lasers. However, the optimal pulse duration for small leg veins has not been established in human studies with a Nd:YAG laser. OBJECTIVES: The purpose of this study was to investigate a range of pulse durations to determine an optimal pulse duration for clearance of leg veins. STUDY DESIGN/MATERIALS AND METHODS: After mapping and photo documentation of the leg veins to be treated, a variable pulse duration Neodymium:Yttrium Aluminum Garnet (Nd:YAG) laser (3-100 milliseconds) was used in a single test site session. Pulse durations of 3, 20, 40, 60, 80, and 100 milliseconds were used. At the 3-week follow-up, the optimal pulse duration was defined as that pulse duration which resulted in the most complete clearance of vessels with the least side effects. Up to 20 vessels were then treated using the established "optimal" pulse duration. Final evaluation was at 16 weeks after the initial visit. Three blinded observers rated the percent of vessels completely cleared based on initial and final photographs. RESULTS: Eighteen patients completed the study. Fluence thresholds for immediate vessel changes varied depending on spot size and vessel diameter, with larger fluences required for smaller spot sizes and smaller vessels. Shorter pulse durations (< or =20 milliseconds) were associated with occasional spot sized purpura and spot sized post-inflammatory hyperpigmentation. Longer pulse durations (40-60 milliseconds) achieved superior vessel elimination with less post-inflammatory hyperpigmentation. With a single laser treatment, 71% of the treated vessels cleared. CONCLUSIONS: Compared to shorter pulses (<20 milliseconds), longer pulses may provide gentler heating of the vessel and a greater ratio of contraction to thrombosis.

Adult↗

The new-generation, high-energy, 595 nm, long pulse-duration, pulsed-dye laser effectively removes spider veins of the lower extremity.

BACKGROUND AND OBJECTIVES: Lower-extremity spider veins are a cosmetic problem that poses formidable clinical difficulty for laser removal. They are significantly harder to remove than facial telangiectasias. A new-generation, pulsed-dye laser (PDL), capable of administering pulses that clinically behave like true 40-millisecond pulses has been developed, by doubling the number of sub-pulses comprising each laser pulse. STUDY DESIGN/MATERIALS AND METHODS: Fifteen subjects with Fitzpatrick skin types I-III were enrolled in the study and treated to 35 sites. Subjects were treated three times at 6-week intervals using an average fluence of 20.4 J/cm(2), a 3 x 10 mm spot, and a dynamic cooling device to protect the epidermis. Digital photographs were taken before initiating treatment and 8 weeks following the final treatment. RESULTS: Mean improvement scores using a 4-point scale as rated subjectively by the treating physician were 0.92 (<25%), 2.7 (approximately 40-50%), and 3.6 (approximately 65-75%), 6 weeks following 1st and 2nd treatments and 8 weeks following the 3rd and final treatment, respectively. Improvement was also determined by three physicians, rating digital photographs and blinded as to which photographs were pre- or post-treatment. They rated improvement as mild (0-25%) in 10.5% of photographs, moderate (26-50%) in 15.2%, marked (51-75%) in 38.1%, and excellent (76-100%) in 6.3%. There was no textural change in any treatment site. CONCLUSIONS: The new-generation, high-energy, 595 nm, long pulse-duration, PDL effectively removes lower-extremity spider veins in subjects with skin types I-III.

Adult↗

Macrocephaly-cutis marmorata telangiectatica congenita syndrome--prenatal signs in ultrasonography.

A new case of macrocephaly-cutis marmorata telangiectatica congenita (M-CMTC) syndrome is described. The patient presented typical congenital findings in utero, although the syndrome was diagnosed postnatally. The M-CMTC syndrome should be considered when there is a marked fetal overgrowth and progressive macrocephaly with no indications of maternal hyperglycemia or fetal hyperinsulinism. Our patient also had unilateral pleural effusion, curved femur and frontal bossing.

Abnormalities, Multiple↗

Cytogenetic investigations in a new case of Bloom's syndrome.

Cytogenetic studies of an 8-year-old caucasian girl with typical but mild manifestation of Bloom's syndrome showed a characteristic increase of homologous chromatid translocations and prematurely condensed chromosomes. The average frequency of sister chromatid exchanges (SCE) in lymphocytes with 133 was much higher than in skin fibroblasts with 49. The inter- and intrachromosomal distributions of SCE in lymphocytes were analyzed.

Abnormalities, Multiple↗

Sister chromatid exchange and cell cycle in fibroblasts of Bloom's syndrome.

Sister chromatid exchange (SCE) has been studied in the fibroblasts of five Bloom's syndrome patients, one heterozygote, and two normal individuals. The high frequency of SCE already known in the lymphocytes of Bloom's syndrome was also found in the fibroblasts of all five patients. However, populations with low and high frequency of SCE were not found. In addition, chromosome aberrations appeared with a lower frequency. The cell cycle duration in the Bloom's fibroblasts appeared to be similar to that in the normal cell line, and the difference in the growth pattern appeared to be due to the variation in the mitotic index. The cell cycle lasted about 24 h in at least four of the Bloom's lines studied during the present experiments.

Cell Cycle↗

Frequency of sister chromatid exchanges in Bloom syndrome fibroblasts reduced by cocultivation with normal cells.

Cocultivation of fibroblast cells from a male patient with Bloom syndrome (BS) and a female control reduced the rate of sister chromatid exchanges in the BS cells from a mean of 54 SCE per metaphase (range 42--65) to 41 (range 24--59). Medium used to culture control cells for 48 h also reduced the rate of SCE (from 40--65 to 33-54), whereas medium used for only 24 h altered the SCE rate only slightly (to 39--61). Dialyzed medium concentrate with molecular cutoff at 15,000 did not alter the SCE rate. These initial studies suggest that normal cells produce an agent, presumably lacking in BS cells, that is capable of mitigating the chromosomal manifestation of the BS mutation (bl) in bl/bl cells.

Adolescent↗

[Bloom's syndrome].

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Abnormalities, Multiple↗

Sister chromatid exchanges and chromatid interchanges in bloom's syndrome.

A comparison is made between the incidences of sister chromatid exchanges (SCE) per chromosome and group of chromosomes and breakage, visible at metaphase like open gaps, breaks, and breaks involved in chromatid interchange formation (CI) in Bloom's syndrome. It can be shown that the two levels of breakage SCE and CI are not correlated as to the locations. The discussion deals with possible interpretations of preferential breakage and reunion at certain homologous chromosomes and the difficulties today to understand SCEs.

Chromosome Aberrations↗

Mitotic recombination and segregation of satellites in Bloom's syndrome.

Mitotic recombination in satellite stalks--a phenomenon often difficult to distinguish from satellite association--was studied in a sister and a brother with Bloom's syndrome. Segregation after recombination was analyzed in the lymphocytes of the sister who had Q-bright satellites. Her cells varied greatly both in regard to the acrocentrics which displayed Q-bright satellites and the number of such satellites per cell. In 58 cells a total of 31 different patterns were seen. In 83 cells of 6 controls who also had Q-bright satellites on at least one acrocentric chromosome, not one cell was found in which the pattern differed from that characteristic of the person. Obviously exchanges between satellite stalks in patients with Bloom's syndrome are fairly frequent (estimated lower limit 6/1000) and very rare in persons who do not have this syndrome (estimated 0.1/1000).

Chromosome Aberrations↗

Replication bypass model of sister chromatid exchanges and implications for Bloom's syndrome and Fanconi's anemia.

A model of the sister chromatid exchange (SCE) process is outlined as a replication mechanism to bypass DNA crosslinks. The model suggests that when normal bidirectional replication advances from both sides towards a crosslink along the two opposite parental strands, the complementary parental strand segments can be temporarily displaced at each contralateral 5' side from the crosslink. The free ends produced in this first step will be terminally aligned but will have opposite polarity. The second step of the bypass can, however, be completed by either of two rejoining processes--terminal ligation of the free ends via nascent Okazaki pieces or aberrant complementation by overlapping the free ends. This bypass mechanism (1) allows replication to continue past a crosslink leaving it intact but (2) results in the switching of parental strands and their attached incomplete nascent strands above and below the crosslink site producing an exchange between sister chromatids. This model is compatible with the findings of current SCE studies using the new BUDR/stain techniques as well as with previous autoradiographic studies. It also suggests that the chromatid breaks and deletions in Fanconi's Anemia represent a defect in step two of the replication bypass mechanism and that the high frequency of SCE's and quadriradials in Bloom's Syndrome represent the SCE overload effects of a defect in crosslink repair.

Anemia, Aplastic↗